Comparative virulence of opacity variants of Neisseria gonorrhoeae strain P9

Abstract

The invasive properties of 9 variants of N. gonorrhoeae strain P9 known to vary in their surface composition were investigated. Relative virulence was evaluated by their cytotoxic effect on Chang (human conjunctiva) epithelial cell monolayers. Piliated variants P9-2 (with .alpha. pili) and P9-20 (with .beta. pili plus protein II) showed increased ability to kill the target cells compared with the prototype P9-1 (lacking pili and additional outer membrane proteins). Two nonpiliated variants, P9-11 (with proteins IIa and IId) and P9-19 (with proteins II and IIc), were also relatively more virulent compared with P9-1. Enhanced attachment was exhibited by piliated and some nonpiliated variants: .beta.-piliated P9-20 (with protein II; MW 29,000) and nonpiliated P9-16 (with protein IIb; MW 28,000) were the most effective in adherence to the target monolayers.